Speed-dependent motor-controlling apparatus.



S. H. KEEPER, DEGD.

M. A. KEEPER. ADMIMSTRATBIX. SPEED DBPBNDENT MOTOR CONTROLLINGAPPARATUS. APPLICATION FILED MAY 29, 1911. RENEWED MAY 26. 1914.

1,124,142. Patented Jan.5,1915

2 SHEETS-SHEBT 1.

S. H. KEEPER, DEGD. M. A. KEEPER, ADMINISTRATRIX.

SPEED DBPENDENT MOTOR CONTROLLING APPARATUS. APPLICATION FILED MAY 29,1911. RENEWED MAY 26, 1914.

1,124,142. Patented Jan. 5, 1915.

2 SHEETS SEEET 2.

THE NORRIS PETERS (7a.. PHOTOJJYHQ, WASHIMJLIM u c.

UNITED STATES PATENT. ornion.

SAMUEL I-I. KEEFER, OE PLAINFIELD, NEW JERSEY; MAE E. KEEFER,ADMINISTRATRIX OF SAID SAMUEL H. KEEFER, DECEASED, ASSIGNOR TONILES-BEIVIENT-POND COM- PANY, OF YORK, N. Y., A CORPORATION OF NEWJERSEY.

SPEED-DEPENDENCE MOTOR-CONTROLLING APPARATUS.

Specification of Letters Patent.

Patented Jan. 5, 1915.

Application filed May 29, 1911, Serial No. 630,030. Renewed May 26,1914. Serial No. 8t1,154.

To all whom it may concern:

Be it known that I, SAMUEL H. Knnrnn, a citizen of the United States,and a resident of Plainfield, in the county of Union,

State of New Jersey, have invented certain Improvements inSpeed-Dependent Motor- Controlling Apparatus, of which the following isa specification.

One object of my invention is to provide apparatus for use in connectionwith electric motors, particularly those of the shunt or compound woundtype, which shall automatically act to cut off current from the motorwhenever the current flowing either in its armature or in its fieldcircuit increases beyond a predetermined amount or when the combinedaction of both of said currents exceeds a predetermined limit; it beingespecially desired that the apparatus shall among other things dependfor its action upon the speed of the motor.

I further desire to provide a system of motor control. which shallinclude circuit opening means capable of actuation by either of two ormore coils, as the case may be, which coils shall be so connected as tobe directly in circuit with orin some way dependent upon the armatureand field circuits of the motor in order that they may be capable ofacting either independently or together to automatically break the motorcircuit whenever the current flow in these elements of the motor risesabove. predetermined amounts. I

Another object of my invention is to provide an apparatus particularlydesigned to govern the amount of current flowing to either the armatureor field of an electric motor and thereby prevent variation in the speedof the motor beyond predetermined points; it being desired that thearrangement shall be such as to cut off current from the motor eitherwhen the flow of such current through the armature exceeds such a pointas might injure said armature or the machine driven thereby, or wheneverthe field current has been so far varied as to bring the speed to such apoint as to overload the gearing or other, equivalent parts of a machinedriven by the motor, or when the armature andfield currents consideredtogether exceed safe amount.

These objects and other advantageous ends I secure as hereinafter setforth, reference being had to the accompanying drawings, in which Figure1, is a side elevation partly in section and to some extent diagrammaticillustrating a relatively simple form of my invention; Fig. 2, is a sideelevation also partly in section showing a modified form of theinvention in which a permanently energized coil is caused to cooperatewith a Winding in circuit with the armature of the motor in order toaccomplish the de sired results; Fig. 3, is a fragmentary frontelevation illustrating a detail of the construction of part of theapparatus shown in Fig. 2; Figs. 4 and 5 are diagrammatic viewsillustrating special forms of my invention, and Fig. 6, is adiagrammatic view of a motor driven machine with its associapredetermined ated apparatus arranged according to my or both oftwocoils & or 5. One of these coils as 4 is connected in series with theshunt field winding 2, while the other is in series with the armature 1of the motor. The circuit breaker in this case consists of a supportingbase 6 of insulating material on which is pivotallymounted a movable armor blade 7, connected through a flexible conductor 8 with a terminal 9to which is connected one end of the coil 5 whose opposite end isconnected to one of the armature terminals. This arm or blade 7 isprovided with a handle 10 and its upper end carries a contact plate 11designed to first engage an auxiliary contact 13 and then a main contact12 when moved to its closed position. A terminal 14: is connected to themain contact 12 which in turn is connected to one of the current supplymains, in the present instance the negative. The two coils 4 and 5 aremounted within a casing 15 having a vertically movable core 16 uponwhich said coils act. This core in turn is placed to act upon a triplever 1'7 designed to engage a cross pin 18 connected to one or morelinks 19 shown in dotted lines; the upper end 01 this lever being hookedso as to retain the arm or blade 7 in its closed position under normalconditions. One or more other links 20 are pivoted to the casing 15 andlikewise engage the cross pin 18.

One terminal each of the field and armature of the motor is connected tothe second current supply main, in the present instance the positive,and under operative conditions it is obvious that if more than apredetermined amount oi current flows through the armature of the motorand hence through the coil 5, the latter will draw upwardly the core 16so that it is caused to strike onearm oi. the trip lever 17, thereby somoving this as to cause it to release the pin. As a result the arm orblade 7 is forcibly turned on its pivot either under the action ofgravity or by means of suitable springs, such for example, as a spring13 on which the auxiliary contact 13 iscarried. The contact is thusbroken between the plate 11 and contacts '12 and 13, and current is cutoli from the motor.

The coil at is of such design that in case the .i'ieldcurrent of themotor increases beyond a predetermined point, it likewise will forciblydraw upward the core 1.6 and also cause release 01 the holding pin 18and separation of the contacts 11, 12 and 13, even though the armaturecurrent of the motor may be well below its allowable maximum. Such anarrangement of apparatus is particularly desirable in combination with amachine tool driven by a motor. In such case it is desirable that themotor circuit shall be opened to automatically stop the machine in. casethe motor should be dangerously overloaded and for this purpose theincreased armaturecurrent would, as above explained, su'liicientlyenergize the coil 5 to accomplish this end. So far as I am aware, nomeans has ever been provided whereby the motor circuit would beautomatically opened in case this same motor should be usedat a reducedspeed and in such manner as to oangerously overload the gearing or theequivalent parts of the machine to which it was attached. By myinvention, however, the coil eL may be so arranged as to act with thecoil 5 to cause the opening of the motor circuitainder these conditions,for in such case the field current would naturally have been increased,with the result that said coil 1 with the coil 5 actuate the core 16 torelease the circuit controlling arm 7. The coils .1: and 5 thus acttogether to trip the breaker at an amperage dependent on the load andmotor speed.

As is obvious, there are a number of ways of securing the same desirableresult as that above indicated, with slight modifications of theapparatus described, as for example in Fig. 2, I have so arranged thetwo coils which are respectively in circuit with the armature andfieldof the motor that these act on different and widely separated parts ofthe circuit breaker, although they are both capable of causing openingof the motor circuit whenever the armature current or the field currentrises above predetermined safe amounts or when the combined action ofthese two currents exceeds a predetermined point or limiting amount. In.this case the circuit breaker is provided with a pivotally mounted bladeor arm 7, to one end of which is connected a core or plunger 25 acted onby the coil 14, which as bel ore, is connected in circuit with the motorfield. winding 2. Said arm or switch blade 7 likewise has an. armatureplate 26 placed to be acted on by an electromagnet 27 having in thisinstance a plurality of windings, of which that indicated at 5 isconnected in series within the armature 1 of the motor. The secondwinding 28 of this magnet is permanently connected across the currentsupply mains although in such manner as to be, opened when the motorcircuit is opened by the movement of the blade 7. In this instance thecoils 5 and 28 are so wound that as long as the motor is supplied. withcurrent not exceeding the safe and predetermined amount, they cause thecore 27 and its associated parts to so act on the armature plate 26 asto retain the arm or blade in a position to permit current to flow tothe motor. If. however, the armature current in the coil 5 increasesbeyond a predetermined amount, this latter coil overcomes the effect ofthe coil 28 by neutralizing the same, whereupon the switch arm 7 ismoved to its open posi tion either by a spring or by action of the coil14 on the core 25. At the same time if the field current of the motorincreases beyond the predetermined safe amount, the coil =14- is so farenergized as to draw the core 25 inwardly and turn the arm 7 on itspivot to move its plate 26 away from the core 27, regardless of theaction of the permanently energized core 28. In this instance the arm 7is provided at its upper end with a pair of auxiliary contacts 29 soplaced as to engage fixed auxiliary contacts 30 electrically connectedto the terminal 14.

In another form of-my invention I may, as before, provide a circuitbreaker or automatic switch having a core 16 acted on by a coil 5 inseries with the armature of the motor and also acted on by a second coil31 which, as shown in Fig. 4:, instead of being in series with the fieldis in shunt thereto. In this case I provide not only the fieldresistance 3 but a secondary body of resistance 32 designed to be usedin circuit with the second winding or coil 31; the arrangement beingsuch that this latter resistanceis decreased by such a movement of therheostat arm 33 as is necessary to decrease the resistance in circuitwith the field winding 2 of the motor. In order that the variation inthe shunt field current may be, as nearly as possible, inverselyproportional to the speed of the .motor when the latter is varied, I mayconnect any desired or suitable coil 34 in shunt to the field resistance3 as shown in Fig. 5, this coil if desired being the winding of thebrake magnet commonly used in connection with certain classes of motordriven machinery. In any case, however, it is seen that I provide meanswhereby the motor circuit is broken whenever either the armature or thefield current rises above a predetermined amount or when the combinedeffect of these currents exceeds such an amount, thereby preventinginjury both to the motor as well as to the machine driven thereby.

In Fig. 6, I have shown a motor driven machine 35 connected to a motor12 through power transmission mechanism 36, the motor being equippedwith the circuit breaking device designed and arranged to operate asheretofore described.

I claim 1. A system including a motor having an armature and a shuntfield winding; with means for automatically opening the motor circuitwhen the current either in the armature or in the field rises abovepredetermined amounts.

2. A system including a motor having an armature and a shunt fieldwinding; with means for automatically opening the motor circuit bothwhen the current in the arma ture exceeds a predetermined amount andalso whenever the motor operates at a predetermined speed below thenormal.

3. A system including a motor having an armature and a shunt fieldwinding; with a circuit breaking device for the motor; said devicehaving a plurality of windings respectively in circuit with the fieldwinding and with the armature of said motor; and means controlled bysaid windings for break-- ing the motor circuit whenever either thearmature or the field currents exceed predetermined amounts.

4. The combination of a motor having an armature and a field winding; aswitch connected in the motor circuit and including a movable member;coils respectively connected to have the current flow in them vary withthe current flow in the armature and field windings respectively; withmeans whereby said coils are caused to act upon the movable switchmember so that the fiow of current above a predetermined amount ineither of them will cause opening of said switch.

5. The combination of a motor having an armature and a field winding; abody of resistance for controlling the flow of current to said fieldwinding; a shunt to said resistance; a switch in the motor circuit; andmeans for governing the opening of the movable member of said switch,the same including two windings respectively in circuit with thearmature and field of the motor; and means acted on by the windings forautomatically causing opening of the switch when more than predeterminedamounts of current flow in either of said windings.

6. The combination of a machine having power transmitting mechanism; anelectric motor for actuating said machine through said mechanism; andmeans for automatically opening the motor circuit whenever the motorspeed is reduced below the normal to a point such as would overload thepower transmitting mechanism without overloading the motor.

7. The combination of a machine having power transmitting mechanism; amotor for driving said machine through said mechanism; and automaticmeans for opening the motor circuit both when the armature current ofsaid motor exceeds a predetermined amount and also when the motor isoperating at a speed below the normal such as would overload the powertransmitting mechanism without overloading the motor.

8. The combination of a machine including power transmitting mechanism;a motor for driving said machine through said mechanism; with a devicefor automatically breaking the motor circuit both when the total load onthe motor exceeds a predetermined amount and also when the load on thepower transmitting mechanism exceeds a predetermined amount at a speedof the motor below the normal.

9. The combination of a machine includ ing power transmission mechanism;a motor for driving said machine through said mechanism; and means forautomatically opening the motor circuit both when the armature or thefield currents of the motor exceed predetermined amounts and also whenthe sum of said currents exceeds a predetermined amount.

10. In an electrical system, a motor stopping device comprising, incombination, a motor having an armature and shunt field windings,circuit making and breaking &

means, and means adapted to influence the operation of said first means,said second means being influenced by and responsive to conditions inthe circuit containing said a1- niatui'e and said shunt field windingsre spectively.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscriblng wltnesses.

SAMUEL H. KE *JFER.

Vitnesses WILLIAM E. BRADLEY, VVM. A. BARR.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, 1). C.

